CLOSE AND COLD NEIGHBOUR OF OUR SUN DISCOVERED

This artist's conception shows the object named WISE J085510.83-071442.5, the coldest known brown dwarf. This cool star-like body is as frosty as the North Pole. It is also the fourth closest system to our sun, at 7.2 light-years from Earth. Image Credit: Penn State University/NASA/JPL-Caltech.

ByANDY FLEMING

NASA's Wide-field Infrared Survey Explorer (WISE) and Spitzer Space Telescope have discovered what appears to be the coldest "brown dwarf" known - a dim, star-like body that, surprisingly, is as frosty as Earth's North Pole.

 Images from the space telescopes also pinpointed the object's distance to 7.2 light-years away, earning it the title for fourth closest system to our sun. The closest system, a trio of stars, is Alpha Centauri, at about 4 light-years away.

"It's very exciting to discover a new neighbour of our solar system that is so close," said Kevin Luhman, an astronomer at Pennsylvania State University's Centre for Exoplanets and Habitable Worlds, University Park.

 "And given its extreme temperature, it should tell us a lot about the atmospheres of planets, which often have similarly cold temperatures."

Brown dwarfs start their lives like stars, as collapsing balls of gas, but they lack the mass to burn nuclear fuel and radiate starlight. The newfound coldest brown dwarf is named WISE J085510.83-071442.5. It has a chilly temperature between minus 48 to minus 13 degrees Celsius. Previous record holders for coldest brown dwarfs, also found by WISE and Spitzer, were about room temperature.

SEE THE SUN'S "RING OF FIRE" ECLIPSE - LIVE!

Annular solar eclipse, as seen in these time lapse images taken at the Jansky Very Large Array, west of Socorro, New Mexico on May 20, 2012.

ByANDY FLEMING

On Tuesday 29 April 2014, tomorrow, an annular solar eclipse will occur. Eclipses occur when our moon moves between the Earth and the Sun blocking the Sun's light. Tomorrow's eclipse is known as an annular eclipse and is a little different to what we might think of as a 'normal' solar eclipse where the Sun completely disappears behind the Moon.

Due to the current distance of the Moon from the Earth as it orbits, the relative size of the Moon will not appear large enough in the sky to block out all of the light from the Sun. Instead it will cause the Sun to appear as a bright ring as the outer edges of the Sun are seen shining around the Moon at the height of the eclipse. The resulting ring of light is known as the 'annulus' or 'the ring of fire'.

Sadly this amazing sight will only be visible in a few areas of the world. The total annular eclipse will in fact be visible only from a very remote and uninhabited area of Antarctica where the instant of the greatest eclipse will be at 06:03 UTC. The south of Indonesia and Australia will however get a chance to see at least a partial eclipse.

If you do happen to be lucky enough to catch a view remember that you should never look directly at the Sun when trying to view an eclipse. One of the easiest ways to safely watch it is to create a projection of it. A cheap and easy way it to create your own pinhole camera!

Watch the Annular Eclipse LIVE direct from the Slooh Telescope, Australia

The next annular solar eclipse will not occur until September 2016. Although a little bit of a while to wait the good news is that it should be easier to view. Much of Africa should this time be able to see the event as well as Antarctica, Australia and south Asia.

FEEL THE PB&J (PASSION, BEAUTY, AND JOY) OF THE COSMOS? SHARE IT!

WHEN IT COMES TO STARS, SIZE MATTERS!

Relative sizes of the planets in the Solar System and several well-known stars:

Mercury < Mars < Venus < Earth

Earth < Neptune < Uranus < Saturn < Jupiter

Jupiter < Wolf 359 < Sun < Sirius

Sirius < Pollux < Arcturus < Aldebaran

Aldebaran < Rigel < Antares < Betelgeuse

Betelgeuse < Mu Cephei < VV Cephei A < VY Canis Majoris

ByANDY FLEMING

One of the really awesome and mind-blowing aspects of astronomy is the sheer immense scale of the distances between planets, stars, galaxies and galaxy clusters. Our everyday terrestrial notions of scale, size, and distance must be discarded, even if we just consider a transit between the Earth and Mars. Kilometres first fall as units of measurement, then astronomical units (AU)(one AU is the distance between the Earth and Sun) -- when we start to consider interstellar distances we have to look at light years as units of measurement (the distance that light travels in one year).

If distances become truly 'astronomical', then it comes as no surprise that likewise sizes and masses follow suit. We all think that the Sun is massive, and it is, with a radius of 695,990km, this is 109 times that of the Earth. With a mass of 1.989x1030 kg, the Sun has the equivalent of 333,000 Earth masses, and yet it is still just a run-of-the-mill yellow dwarf class G2 star. As the diagram above shows, although there are many considerably smaller than the Sun (very common red dwarf stars) such as our nearest neighbour Proxima Centauri, there are also stars very much more massive.

ASTRONOMY 101: THE SUN

The Sun is an ordinary star and is the brightest object in our sky.  As such you should certainly never look at the Sun directly and certainly never through binoculars or a telescope.

It’s one of more than one hundred billion stars that populate our Milky Way galaxy.  It’s a gigantic ball of hydrogen 870,000 miles wide.  The Sun has a diameter 109 times that of the Earth and is one third of a million times its mass.

The Sun collapsed from a cloud of hydrogen gas approximately 4.5 billion years ago.  The pressure and temperature of the hydrogen in its centre became so great that nuclear fusion chain reactions started where 600,000,000 tons of hydrogen are converted into helium each second.  In the process, under Einstein’s famous equation E equals M C squared, a small amount of mass is lost as energy including light.

This energy is what we and all living things depend on for our existence.  The visible light we see from the Sun takes eight minutes to travel the 93 million miles before it reaches our eyes and is only a small part of the energy released from our star.  Its nuclear reactions also produce vast quantities of ultra violet light along with deadly x-rays and gamma ray radiation.  Indeed if it wasn’t for the Earth’s protective magnetic field this radiation would strip off our life-giving atmosphere and all life on Earth would be burnt to a crisp.

Temperatures at the core of our star Sun reach a staggering 10 million degrees Celsius, but it’s surface is less hot at about 5,000 degrees Celsius.

The Sun consists of approximately 75% hydrogen and 25% helium and is halfway through its life.  In 4.5 billion years it will run out of its hydrogen fuel and will start to fuse helium into even heavier elements.  In the process it will become a bloated Red Giant star that will engulf the orbit of the inner planets.  Finally it will puff off its outer layers as a planetary nebula before contracting to the size of the Earth.  It will have become a white dwarf star made of pure carbon diamond… a cosmic ember.  I don’t think however we’ll be around to see it!

FEEL THE PB&J (PASSION, BEAUTY, AND JOY) OF THE COSMOS? SHARE IT!

UK TREATED TO RARE DISPLAY OF THE NORTHERN LIGHTS

The Northern Lights, seen over St Mary's Island, Whitley Bay, Tyne and Wear.

ByANDY FLEMING

The UK was treated to a rare glimpse of the Northern Lights after the natural display lit up skies across the country. One of nature’s true wonders, the Aurora Borealis could be seen as consisting of spectacular “curtains” of red and green lights, and was visible as far south as Gloucestershire, Essex and Norfolk last night (February 28).

But those in Scotland and northern England got the clearest view, with many taking to Twitter to share their experiences. Daisymay wrote: ‘You could see the Aurora Borealis in the Isle of Skye. So damn perdy.’

Richard Wilson, from Guildford, Surrey, who saw it from the air, added: ‘Great view of the Northern Lights from 30,000 feet over Scotland tonight. Awesome sight!’

The Light formations are usually only visible in the more northern parts of the UK so Alex Green, who works for the National Trust in Norfolk, was surprised when he saw them further south.